Pilot check



June 4, 1929. F KRAEMER 1,716,359

PILOT CHECK Filed April 18, 1927 IN ve 1v r02.-

' f-RANK HRAEMER,

Patented June 4, 1929.

, UNIT FRANK KRAEMER, 0F LOS ANGELES, CALIFORNIA, ASSIGNOR TO WILLIAM H. GESTRING.

PILOT CHECK.

Application filed April 18,

This invention relates to devices used in connection with water-heaters for controlling the ignition of the heating medium.

One of the objects of this invention is to eliminate any turningon of the main gas burner in a water-heater if the pilot burner has once been extinguished accidentally or otherwise.

. Another object is to include a thermostatic element, operative by the pilot burner for con trolling the fuel supply.

Other objects will appear from the follow ing description and appended claims as well as from the accompanying drawing, in which- Fig. 1 is a front elevation of a pilot burner control, including an electric switch to oper ate a gas control and including also a thermostat, operative by surrounding water when applied to the water-heater, the Water thermostat being broken oif to facilitate the 1llustration.

Fig. 2 is a perspective view of terminals mounted on an insulated block for electrically controlling the gas supply through the device illustrated in Fig. 1.

Fig. 3 is a fragmentary side elevation of the electric switch lever.

Fig. 4 is a fragmentary top plan view of the insulated terminals of Fig. 2 and the switch lever of Fig. 3.

As illustrated in Fig. 1, the main gas connection is indicated at 5, below the instrument case 6. This main gas connection is controlled by a valve 7 inserted in the connection, operative by a solenoid 8 in the instrument box 6. This solenoid 8 is inserted into any suitable electric circuit in series with contact terminals 9 and 10. These contact terminals are normally spaced so that the electric circuit is thereby interrupted. For closing the circuit a switch lever 11 is pivotally mounted at 12.

The switch lever 11 is normally held in inoperative position by the thermostat 13. The thermostat 13 is normally inserted into the inside of a water-heater, so as to become influenced by the temperature of the water in the heater. When the water in a heater has reached a desired temperature the thermostat 13 is in expanded position with its controlling end 14 in its uppermost position pressing by its adjusting screw 15 against the lever end 16. The lever end 17 is thereby forced in the direction of the arrow 18, in which manner the connecting rod 19 is caused to force the switch 1927. Serial N0. 184,758.

lever 11 into the inoperative position in which this lever is illustrated.

The pilotburner tube 20 receives its gas supply from the main connection 5, having its line discharging aperture 21 disposed to discharge the gas against the thermostatic bar 22. When this discharging gas is ignited it naturally heats and thereby expands the thermostatic bar 22 so as to bring the control end 23 to its lowermost position, so that the set screw 24 frees the lever end 25. When the lever end 25 is released in this manner, the leverend 26 is free to move in the direction of the arrow 27 to the extent of the slot 28 as long as the lever end 17 with the connecting rod 19 forces the switch lever 11 in the direction of the arrow 18. I I

\Vhenever the temperature of the water in the heater decreases so as to lower the control end 14 of the thermostat 13, the lever end 17 is free to move in a direction opposite to the arrow 18, in which direction this lever end and the connecting rod 19 are forced when so freed by the spring 29, thereby bringing the contact switch against the contact terminals 9 and 10, bridging the gap between these terminals 9 and 10. At this moment current may pass through the contact terminals from the lead 30 and through the lead 31 and further through the solenoid 8 to the lead 32, through which the solenoid affects the valve 7 in the main gas connection 5 to supply a full force of gas to the water-heater.

The water-heater is not shown in the drawing, but it will easily be understood from the above that gas can be supplied through solenoid actions in the manner described.

The switch lever 11 is provided with equalizing means in form of a yielding cross bar 33 by which the contact members 34 are equal ly pressed against the terminals 9 and 10 in the manner illustrated in Fig. 4.

Whenever the pilot burner is extinguished accidentally or otherwise, the thermostat bar 22 contracts to bring the control end 23 to its uppermost position, whereby the lever end 25 is held in its uppermost position so as to hold the lever end 26 pressed in a direction opposite to the arrow 27, wherebythe switch lever 11 is held in inoperative position. When so held in inoperative position the thermostat 13 is unable to effect a closing of the switch, even ifthe water in the heater gets cold, since a mere releasing of the lever end 16 and thereby of the lever end 17 will not allow the switch lever 11 to move into contact making position against the contracted thermostat bar 22.

It is therefore made impossible to open thefuel supply of a water-heater whenever and as long as the pilot burner is extinguished. Explosions and similar accidents with Waterheaters are therefore made impossible when conlt-rolled by a pilot check as described herewit 1.

After the pilot burner has been extinguished it can easily be ignited again near the small aperture 21, and as soon as ignited it will heat the thermostat bar 22 and the Whole instrument will work in a normal manner again as soon as the thermostat bar 22 is heated to the extent to allow the switch lever 11 to close. 1

The discharging of gas from the small aperture or jet 21 in the pilotburner pipe 20 as well as the thermostat bar 22 is indicated at 35 in Fig. 1.

Having thus described my invention, I claim:

1. In a pilot check of the class described,

' in combination with an electric switch for controlling a main gas supply of a waterheater, a thermostat in operative connection with said switch and adapted to be operative by temperature changes in the heater, and a pilot burner embodying an independent sechold the switch inoperative regardless of movements of the first-named thermostat.

2. In a pilot check of the class described, a solenoid controlled fuel supply, a thermostat adapted to extend into a water-heater to be influenced by the temperature of the water 7 in the water-heater, an electric circuit in operative connection with said solenoid including normally spaced terminals, a spring-controlled switch, a lever mechanism in operative connection with said switch and with said thermostat by which said switch is held inoperative when the thermostat is expanded, a pilot burner, a thermostat element disposed to be expanded by the heat originating from the pilot burner, and a second lever mechanism in operative connection with-said element and the first-named lever mechanism disposed to check the movements of the firstnamed lever mechanism when the pilot burner is not burning and the cooperating thermostat elementis not expanded by the pilot burner.

my invention I have signed my name.

FRANK KRAEMER. 

